To: | [email protected] |
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Subject: | LF: Re: [rsgb-lf-group] FW: JT9-5 Drift |
From: | Andy Talbot <[email protected]> |
Date: | Mon, 7 Jan 2019 13:13:46 +0000 |
Cc: | "[email protected]" <[email protected]> |
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The JT9-5 tone spacing is 0.29Hz, so those drift figures correspond roughly to a bit less than one complete tone spacing in the transmission period. Which makes intuitive sense. The error correction allows it to "lose" the few symbols at the end where it has drifted too far, while those at the start are near enough to work normally. (Pure speculation) The soft decision process in the decoder algorithm will base its metric on how far the received signal is away from where it ought to be, so a tone that has drifted into an adjacent bin may still have a quite strong weighting applied. BTW Rik, you still appear to be copying these posts to the now-dead Yahoo Group Andy On Sun, 6 Jan 2019 at 10:48, Rik Strobbe <[email protected]> wrote:
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